(1) Field
The present disclosure relates to a flexible display device.
(2) Description of the Related Art
An organic light emitting diode (OLED) display may have a bending characteristic when a flexible substrate, such as a plastic film, is used instead of a rigid substrate, such as glass.
That is, a flexible OLED display includes a plastic film, a pixel circuit that is formed on the plastic film, and, for example, a light emitting element, such as an organic light emitting diode.
A plurality of inorganic layers, such as an interlayer insulating layer, a gate insulating layer, a buffer layer, and/or a barrier layer, may be formed on the plastic film.
In a manufacturing process of a flexible display device, a plastic film is positioned on a rigid carrier substrate, such as glass, and after forming a pixel circuit, an organic light emitting diode, and a plurality of inorganic layers on the plastic film, the plastic film including the pixel circuit, the organic light emitting diode, and the plurality of inorganic layers is separated from the carrier substrate. Such plastic film may also be referred to as a flexible display panel.
After being processed as such, the flexible display panel is cut to a panel size.
FIG. 1 is a cross-sectional view of the flexible display panel illustrating a cutting region thereof.
For a simplified drawing, the pixel circuit and the light emitting element are not illustrated in FIG. 1; however, the plurality of inorganic layers that are formed on the plastic film are illustrated.
As shown in FIG. 1, when the plastic film 2 laminated with a plurality of inorganic layers 12, 14, 16, and 18 is cut, an upper protection film 6 and a lower protection film 4 are laminated on top and bottom surfaces of the plastic film 2 (e.g., on top and bottom surfaces of the display panel).
In order to cut the flexible display panel with the upper and lower protection films 6 and 4 respectively laminated thereon, a mechanical cutting method is used to forcibly cut the flexible display panel during which the flexible display panel is pressed due to contact from a cutting knife (e.g., the mechanical cutting method applies pressure to the flexible display panel).
As such, when the flexible display panel is cut by a mechanical cutting method, cracks may occur in the inorganic layers depending on an amount of impact or force delivered to the panel at the time of cutting.
Further, because the cutting knife penetrates through the upper and lower protection films, the flexible display panel may bend when being cut, and when this occurs, cracks due to such bending may occur in the flexible display panel.
The cracks occurring in the flexible display panel are linearly formed at (e.g., around) a cutting line (e.g., the cracks extend in a generally linear direction).
Accordingly, the linearly formed cracks can be transmitted to (e.g., may extend or migrate to) an active region of the panel when performing a subsequent process or a reliability test, thereby causing shrinkage and/or reduced performance of the panel.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.